The Top Shells and Dolphin Shells 



Atlantic forms are more depressed than those of the Mediter- 

 ranean. 



Genus LIVONA, Gray- 

 Shell top-shaped, heavy, large, with deep umbilicus; whorls 

 rounded; aperture roundish; outer lip sharp-edged; operculum 

 concave outside, thin, smooth, chestnut inside, with olive green 

 muscle scar; body fringed with numerous cirrhi. 



The West Indian Top Shell (Livona pica, Linn.) is found 

 in Charlotte Harbor, West Florida, but not in such abundance as 

 farther south. It is a popular sea food in the West Indies and in 

 Central America. The shell itself has some commercial value; 

 it is sometimes four inches high, oftener smaller; when cleaned 

 and polished it shows a beautiful greenish pearly ground with 

 strong black wavy markings. It lives in great numbers on the 

 rocks and coral reefs, near shore, where it may be seen through 

 the limpid water crawling along, waving two long tentacles ahead 

 and a fringe of cirrhi almost as long on each side of the foot. 

 When the surprised tourist sees one of these large top shells 

 climbing a tree (a very common sight in the islands) he may be 

 sure that the moUusk is dead and its vacated shell is inhabited 

 by a hermit crab. 



Genus CHLOROSTOMA, Swains. 



Shell conical, solid, base of columella toothed, aperture 

 oblique, outer lip smooth within. A large genus, chiefly of Pacific 

 coast species. It is fairly represented in the West Indies. 



The Black Top Shell (C. jimehrale, A. Ads.) is found in 

 the greatest abundance upon rocks on the California coast. It 

 has a heavy black shell, with distinct swelling of the body whorl 

 below the suture. The apex is blunt, the umbilicus closed; 

 the aperture is lined with greenish pearl; there is a white nodule 

 at the base of the columella. The shell is an inch in height and 

 width. 



The Brown Top Shell (C.Jmww^Mm, Phil.), also aCalifornian 

 species, is a clumsy brown thimble in form, about an inch long, 

 with markings of white on the lips and a greenish pearly lining. 

 It lives upon kelp and rocks. 



215 



